The problem with that bullshit is the 100% fatal statistic for that one strain against mice is outside of a lab! hence the term "normally."
In biotechland, all sorts if placebos work wonders because it's the careful care of being in a lab and properly nourished. Notice how NNVC never claimed it was 50% survival va. a placebo in the same lab setting.
They could have simply done a placebo controlled double blinded study (don't let the rodents know either!) but they didn't or they did and didn't report on it. Why?
All sorts of diseases have a lower fatality rating when great comfort, fluids, and nourishment is received. For example, dehydration is listed as the number one complication from dengue fever. In a lab being spoofed water, this is less likely. Maybe 50% less likely.